#include "stm32f10x.h"                  // Device header


void Timer_Init(void)
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    TIM_ETRClockMode2Config(TIM2, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 3);

    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitstructure;
    TIM_TimeBaseInitstructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitstructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInitstructure.TIM_Period = 5 - 1;  // maximum
    TIM_TimeBaseInitstructure.TIM_Prescaler = 1 - 1; //pre division
    TIM_TimeBaseInitstructure.TIM_RepetitionCounter = 0; //only applays to NB Timer(Tim1 and Tim8 in APB2)
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitstructure); /*已初始化就进入中断原因 Generate an update event to reload the Prescaler and the Repetition counter values immediately */
    TIM_ClearFlag(TIM2, TIM_FLAG_Update); //clear 更新flag to 避免马上进入更新中断

    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
    NVIC_Init(&NVIC_InitStructure);

    TIM_Cmd(TIM2, ENABLE);

}



uint16_t Timer_CountGet(void)
{
    return TIM_GetCounter(TIM2);
}

/* IT templete
void TIM2_IRQHandler(void)
{
    if (TIM_GetFlagStatus(TIM2, TIM_FLAG_Update) == SET)
    {

        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
    }
}
*/
